This invention relates to an apparatus for melting and dispensing thermoplastic materials such as thermoplastic adhesives referred to as xe2x80x9chot meltxe2x80x9d adhesives. More specifically this invention relates to a one piece melter tank which is suspended from a chassis which also serves as the housing for the entire assembly of the melting and dispensing apparatus.
There are many known types of apparatus for converting thermoplastic or so-called xe2x80x9chot meltxe2x80x9d materials from a solid state to a molten liquid state. The melted material was maintained in the molten state in the tank in sufficient volume to supply one or more applicators or dispensers. A number of design improvements were made over a period of time to provide greater efficiency of the melt tanks and reduce problems of charring or oxidation of the molten material due to the material being maintained in the molten state for a prolonged period of time.
A grid type hot melt applicator was designed to have the capability of melting a very high throughput of thermoplastic material in a very short time so that the molten material was not maintained in a molten state for prolonged periods of time which could result in degradation of the material. A typical grid type applicator is disclosed in U.S. Pat. No. 3,964,645. Other examples are shown in U.S. Pat. Nos. 3,981,416, 4,474,311, 4,667,850, and 4,821,922. Continued efforts to improve melter apparatus has resulted in the present invention.
A primary object of this invention is to provide a hot melt unit which is simple to construct and assemble and which can be produced at reduced cost to those devices of greater complexity.
Another object of this invention is to provide a low cost tank casting which does not require to of tank flanges which are needed on many of the previous designs.
Another object of the invention is to eliminate the need for providing a supporting base beneath the melt tank and manifold.
A still further object of this invention is to provide a more versatile pump/drive mounting surface.
An even further object of the invention is to provide a simplified one piece melt tank and manifold cast as an integral unit.
These and other objects of the invention will become more fully apparent from the description in the following specification and the attached drawings.
The combination of a melter tank for thermoplastic material and a supporting chassis comprising: a tank having a bottom and a plurality of sidewalls extending upwardly therefrom, forming an open topped tank, the sidewalls of the tank having upper edge portions extending around the top of the tank, heating means associated with the bottom of the tank, a chassis having a top and at least two sidewalls extending downwardly therefrom, a rigid top insulator panel to rest on the upper edge portions of the tank sidewalls, means connecting the tank to the top of the chassis with the rigid insulator panel clamped between the upper edge portions of the sidewalls and an underside of the top of the chassis to suspend the tank from the chassis.